Study of collective flow effects in CC collisions at a momentum of 4.2 GeV/c per nucleon

Directed (in-plane) flows of protons, pions, and projectile light fragments (d, t, 3He, 4He) have been observed by investigating the dependence of the mean transverse momentum in the reaction plane 〈p x 〉 on the rapidity y in the c.m. system for CC collisions at a momentum of 4.2 GeV/c per nucleon. The comparison of our in-plane-flow results of protons with flow data for various projectile/target configurations was made using the scaled flow F s = F/(A 1/3 + A 1/3 ). F s demonstrates a common scaling behavior for flow values from different systems. From azimuthal distributions of protons and π − mesons, out-of-plane (squeeze-out) flow effects have been observed and the parameter a 2 (the measure of the anisotropic emission strength) has been extracted. The quark-gluon string model reproduces the experimental results quite well.

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